Request ID: FOI-2893-2324 Date published: 24 November 2023
You asked
Hi,
I have a few questions regarding the New Tube for London rolling stock, set to be used on the Piccadilly line.
1.Why was the decision made not to have a single set point target saloon temperature?
Given TFL’s answer to question 1, please expand on the reasons below, lettered A-D only if relevant to the decision.
A. Was this decision made on behalf of the size of the tunnels?
B. What is the maximum airflow rate/ temperature deemed inappropriate for the units to evacuate into the tunnels?
C. Was this decision made for maintenance and/or energy-saving purposes?
D. Was this decision made because of power consumption constraints of the current infrastructure?
2. Are the units powerful enough, based on manufacturer specification,(in BTU and KWh) to cool the train by 20ºc in temperatures higher than 35ºc - if not what is the shortfall in BTU and KWh?
3. What is the maximum airflow rate (from the outside of the train to the inside/ being evacuated outside the train following cooling)?
4. Are new ventilation shafts and/or chillers being placed on the Piccadilly line because of the new system during the warmer months?
A. If so, how many of each over the next six years?
B.If not, does TFL expect an increase in deep-level ambient temperatures on platforms during warmer months?
5. What is the train’s expected maximum rate of acceleration with current line infrastructure? Will this change depending on expected signalling system upgrades like the sub-surface lines, if so what will the new maximum be upon completion?
We answered
TfL Ref: FOI-2893-2324
Thank you for your request received by Transport for London (TfL) on 13th November 2023 asking for information about the New Tube for London rolling stock
Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy.
I can confirm that we hold the information you require. Your questions are answered in turn below:
Question 1.Why was the decision made not to have a single set point target saloon temperature?
Answer: This is normal for air cooling systems on trains and is recommended by the relevant industry standard BS EN 14750-1. The principal reason is that passengers will normally be wearing warmer clothing when the ambient temperature is cooler, and are therefore comfortable at lower saloon temperatures. This design specification also reduces energy consumption.
Given TFL’s answer to question 1, please expand on the reasons below, lettered A-D onlyif relevant to the decision.
Was this decision made on behalf of the size of the tunnels?
What is the maximum airflow rate/ temperature deemed inappropriate for the units to evacuate into the tunnels?
Was this decision made for maintenance and/or energy-saving purposes?
Was this decision made because of power consumption constraints of the current infrastructure?
Answer: N/A - as covered in answer 1 above.
Question 2. Are the units powerful enough, based on manufacturer specification,(in BTU and KWh) to cool the train by 20ºc in temperatures higher than 35ºc - if not what is the shortfall in BTU and KWh?
Answer: The air cooling will not achieve a 20ºC reduction in temperature, noting that this is far in excess of what is required to maintain passenger comfort. The cooling performance will be in accordance with the relevant industry standard (BS EN 14750-1) which recommends a target reduction of 6 ºC at 35°C. We do not have data available regarding the cooling power required to achieve a 20ºC reduction.
Question 3. What is the maximum airflow rate (from the outside of the train to the inside/ being evacuated outside the train following cooling)?
Answer: The maximum fresh air rate for a complete 9-car train is approximately 13,000 m3/hr.
Question 4. Are new ventilation shafts and/or chillers being placed on the Piccadilly line because of the new system during the warmer months?
Answer: There are no new ventilation shafts or chilling schemes planned for the current funded stage as temperatures are not expected to increase with the introduction of the new trains with their improved energy efficiency and regenerative braking capability.
A. If so, how many of each over the next six years? B.If not, does TFL expect an increase in deep-level ambient temperatures on platforms during warmer months?
Answer: Due to the improved energy efficiency of the new trains TfL does not expect an increase in deep-level ambient temperatures on platforms during warmer months.
Question 5. What is the train’s expected maximum rate of acceleration with current line infrastructure? Will this change depending on expected signalling system upgrades like the sub-surface lines, if so what will the new maximum be upon completion?
Answer: The maximum acceleration is 1.2 m/s2 on the existing infrastructure The maximum acceleration will remain at 1.2 m/s2 when the signalling system is upgraded.
If this is not the information you are looking for please do not hesitate to contact me.
Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.
Yours sincerely,
David Wells FOI Case Officer FOI Case Management Team General Counsel Transport for London
